Underwater breathing apparatus



16, 1960 c. o. BISS'ET 2,949,113

UNDERWATER BREATHING APPARATUS Filed April 3, 1957 mvsm'on CLAUDE- O,'BISSET MM,M,MV

ATTORNEYS Unite 2,949,113 iatented Aug. 16, 1960 2,949,113 UNDERWATER Bataan-me APPARATUS Claude Ogilvie Bisset, 102 Clive Athol Ame'sho'lf St.-, Braamfontein, Johannesburg, Transvaal, Union of South Africa Filed Apr. 3, 1957, Ser. No. 650,354

Claims priority, application Union of South Africa Apr. '4, 1956 3 Claims. (Cl. 128-142) This invention relates to underwater breathing apparatus for skin divers.

Such apparatus normally comprises a pair of air tubes connected to a mouthpiece with a valve mechanism including a pressure demand valve for controlling the air supply to the mouthpiece and automatically maintaining the air supply pressure at the mouthpiece approximately equal to the ambient water pressure at any depth at when. the diver may be positioned. With such apparatus there is a certain wastage of air due to admixture of. fresh air with exhaled air which is disadvantageous due to the limited air supply available and the danger of accumulating in the apparatus bad air exhaled from the lungs.

It is generally the object of this invention to provide an underwater breathing apparatus in which such wastage of fresh air will not occur.

A further object of the invention is to provide a simple apparatus which Will have extreme delicacy of response to varying pressure conditions and thus facilitate the easy and comfortable breathing by the wearer.

With this invention in a mask covering the nose of. a diver and leaving the mouth exposed, a constant air pressure is provided normally slightly above the ambient water pressure.

In accordance with this invention there is provided an underwater breathing apparatus comprising a mask shaped to cover the nose of a diver, said mask having no air outlet, and an air inlet valve mounted on and connected to discharge into the mask.

A preferred form of the invention suitable for use in an underwater breathing outfit is illustrated in the accompanying drawings in which:

Fig. 1 is a perspective view of a mask with the air regulating valve in place and attached to the compressed air cylinder.

Fig. 2 is a side elevation of the regulating valve and fitting with the cover removed and drawn on an enlarged scale, and

Fig. 3 is a view of the valve shown in Fig. 2, showing its connection to the cover of the fitting.

In the drawing 1 represents a cylinder of compressed air fitted with a reducing valve 2 and connected through a tube 5, to a regulating valve casing 3 attached to and discharging into the mask 4.

The mask has a window 6 mounted in a rubber surround shaped to fit tightly the contours of the face of the diver While providing a compartment covering his eyes and nose. Straps 7 are adapted to clamp the strip 8 round the back of the head to hold the mask 4 tightly against the face.

Adjacent to the mask 4 the tube is connected to a short tube 9 projecting into a chamber 10 in the casing 3. The tube 9 in the chamber 10 is closed except for a small central opening 11 acting as a nozzle for the escape of the air.

A sleeve 12 surrounds the short tube 9 and extends almost to the opposite side of the casing 10 and carries a valve having a fiat resilient end 13 which is adapted to be pressed against the opening 11 to stop the flow of air into the mask 4. The valve stem 14 of the valve 13 extends beyondthe sleeve 12 and contacts one arm 15 of a bell crank lever 16 mounted on a fulcrum 17 secured in the casing 10. This arm 15 is pressed up towards the valve stem 14 by movement of the bell crank lever 16. An adjustable spring 18 may be placed below the arm 15 of bell crank lever 16 for use as hereafter described.

The valve stem 14 has at least two flexible and thin rubber discs 19 which fit the inside of the sleeve 12 and support the valve stem 14 substantially centrally therein. The other arm 20 of the bell crank lever 16 extends upwardly in the casing parallel to the sleeve 12;

The-chamber 10 is closed by a cover 21 which has a central opening 22. Inside the casing 10, is a dia= phragm'23 and fastened to it is a stirrup piece 24 and the arm 20 is threaded through the same so that movements of diaphragm 23 will be positively transmitted to the valve 1 3. The circular edge of the diaphragm 23 will act as a joint between the cover 21 and the edge of the case 3 when they are fastened together as by means of screws through lugs on 21 and into projections 25 on the outside of chamber 10.

An adjustable cap 26 is provided fof regulating the pressure of the spring 18 which is housed in the short tube 27. The spring 18 may be used for forcing and 15; ;to press the valve 13 against the nozzle 11 t6 shut:

off the air supply when apparatus is not in use.

It is found convenient to discharge the air from the opening 11 in tube 9 through an opening 28 in the side of the casing 12. Discharged in this manner the air' does not disturb the movement of the valve stem 14 which as described is carried on the discs 19.

It will be understood that the valve assembly described is well adapted to operate consistently, no matter at what:

will be regulated by the water pressure on the outside of the diaphragm. Once the adjustment is made the desired balance of pressure will be maintained automatically.

A skin diver wearing an underwater breathing apparatus as above described, including the mask 4 over the nose and eyes, will turn on the air from his cylinder 1.. The diaphragm 23 will tend to move outwardly under the air pressure supplied past the valve 13.

If the diaphragm is distended against the water pressure the arm 20 of the bell crank lever 16 will move and in turn move arm 15 to close valve 13. The adjustment of the air pressure in the mask will be such as to be positive to the ambient water pressure. Consequently on such movement of the diaphragm 23 the air entering the mask 4 will be checked by movement of the valve 13. As the diver descends the water pressure will tend to press the diaphragm 23 inwards and such movement will allow valve 13 to open and more air will be admitted to balance the movement of the diaphragm 23 and keep the diaphragm 23 in position against the ambient water pressure.

The air pressure in the mask 4 and in the lungs of the diver will therefore exceed the water pressure, which latter is in proportion to the depth of the diver in the water. The result is that this air pressure in the mask 4 will make it easy for the lungs of the diver to expand and take in a full supply of air even against the pressure of the Water on the divers body which without such air pressure available would tend to make it difficult to expand the lungs.

Air taken into the lungs from the mask 4 will have the efiect of automatically opening the valve 13 to allow the air which has been breathed to be replaced. In this way a supply of air is automatically maintained constantly available in the mask 4. The air is expelled by the diver through his mouth so that the exhaled air is not admixed with fresh air. This will mean that he is breathing into his lungs clean pure air from his air supply at all times. Water cannot enter his mask as the air pressure therein is positive in relation to the water pressure at the depth he is swimming.

The simplicity of operation of the apparatus and reduction in the number of moving parts enable it to be accurately adjusted so that the air supply is substantially equal to the demand which facilitates easy and comfortable breathing.

This invention provides a breathing apparatus having the regulation of its air supply dependent only on a flexible diaphragm in contact with the ambient water pressure and therefore requiring the use of no metal springs.

What I claim as new and desire to secure by Letters Patent is:

1. An underwater breathing apparatus comprising a mask shaped to cover the nose of a diver, said mask being closed against the exit of air and an air inlet valve mounted on and connected to discharge directly into the mask said valve comprising a discharge nozzle, a valve head movable axially to open and close said nozzle, a pressure responsive diaphragm in communication with the interior of the mask on one side and with the surrounding pressure on the other side and a bell crank lever operatively positioned between the diaphragm and valve and positively connected to said diaphragm, a spring adapted to load said bell crank lever and means for adjusting the spring.

2. In combination a breathing mask for skin divers a and a valve assembly for inflating the mask said valve assembly comprising a short tube forming a compressed air supply nozzle, a sleeve surrounding and extending beyond said nozzle, a valve stem and valve positioned in the sleeve to cover the end of the nozzle to block the air flow therefrom, flexible discs supporting the valve stem in said sleeve, a bell crank lever contacting the valve stem, at fulcrum for the lever adjacent the end of the sleeve, a flexible diaphragm in communication with the interior of the mask on one side and with the surrounding pressure on the other side and closing one side of the valve assembly and operatively and positively connected to the bell crank lever, and an outlet in the sleeve adjacent said nozzle for the air admitted by the valve into the mask.

3. In combination a breathing mask for skin divers and valve assembly as claimed in claim 2, a compression spring adapted to force one 'arm of the bell crank lever into contact with the end of the valve stem, at housing therefor in the form of a short cylinder, and a can screwed on the end of the housing to regulate the pres sure on the spring to shut ofi the air supply.

References Cited in the file of this patent l i 

